Prior art bidirectional counters usually increment the count by one in response to a pulse from a transducer indicating movement in one direction and decrement the count by one in response to a pulse from the transducer indicating movement in the other direction. In certain applications, such as for example where the counter is used to display mirror position in an interferometer system, a linear displacement transducer may be employed which provides two output pulses per unit of motion. Also, it is often desirable to display rotary position to one-half degree accuracy with a 720 pulse per revolution rotary encoder. In such situations, it is necessary to divide the displayed number by two. The mere introduction of a divide-by-two circuit ahead of the counting circuits does not provide an acceptable solution, since if motion is reversed the count can be an error by one-half unit.